Method and apparatus for reducing the friction coefficient of roll spools during winding of a web

ABSTRACT

A method and apparatus in winding, wherein a number of separate rolls (13a, 13b, 13c, 13d, 13e, 13f) are formed side by side around separate roll spools (15a, 15b, 15c, 15d, 15e, 15f) placed one after the other while supported by support numbers (11, 12). In order to reduce the friction coefficient of the roll spools (15a, 15b, 15c, 15d, 15e, 15f) before, or at the same time as, the roll spools are placed in the winding position, the ends of the roll spools are treated with an agent that reduces the friction coefficient, or pieces of a material that has a low friction coefficient are placed at the end of the roll spools, and/or the axial thrust force between the roll spools is lowered by passing a pressurized medium through the spool locks.

FIELD OF THE INVENTION

The invention concerns a method in winding, wherein a number of separaterolls are formed side by side around separate roll spools placed oneafter the other while supported by support members.

BACKGROUND OF THE INVENTION

Owing to variations in the cross-direction profiles, for examplethickness, moisture and roughness, of the web to be wound, adjacentrolls are not formed with precisely equally large diameters, in spite ofthe fact that, in principle, precisely equally long component webs arewound into them. Owing to the different diameters of the rolls, the rollspools placed in the roll centers are displaced with the progress ofwinding in relation to one another so that their centers of rotation areseparated and, at the same time, minor variations occur in the angularspeeds of the rolls. Since the roll centers are, however, during theentire winding process, in contact with each other, diverting forcesarise between the ends of the roll spools, and the rolls tend to "jump",in which connection the rolls that are being formed can be damaged.Owing to this detrimental oscillation, in carrier-drum winding, it is,as a rule, necessary to run at a lower speed, i.e. to be content with alower winding speed. which reduces the capacity of the machine and is,thus, uneconomical.

The problem described above has occurred as long as winders of thecarrier drum type have been in use. The seriousness of the problem has,however, varied in the course of years, because the profile of the webproduced in a paper machine has improved and, at the same time, the rollsize and the winding speed have changed to a little extent only. Inrecent years, the diameters of the customer rolls produced have startedbecoming ever larger and, at the same time. the winding speeds have alsoincreased, for which reason the problem of oscillation has been noticedagain: even a little variation of profile in the direction of width ofthe web is cumulated especially during winding of thin paper grades sothat faults in the shape of the rolls which arise from the web profilecause a significant oscillation problem.

In the winding process, a number of different phenomena are effectivewhich attempt to shift the web rolls that are being formed in theiraxial direction:

deflection of the winding cylinders. i.e. carrier drums,

faults in the shape of the rolls arising from uneven profile of the web,and

also the spool locks, which support the roll spools of the lateral webrolls, subject the row of rolls to axial forces when they keep the rowof rolls in the desired location.

The spool locks alone can also produce a compression force applied tothe whole row of roll spools when the roll spools are excessively long:the total length of the roll spools is higher than the regulateddistance between the spool locks.

The phenomena described above can, either alone or together, producesituations in which the ends of the roll spools of the rolls tend to bepressed against each other and thereby to produce a relative supportforce.

Thus, there are several factors that produce a relative axial thrustforce between the rolls. The spool locks, which keep the lateral rollspools in their positions, keep the row of rolls in the correct windingposition in the lateral direction, but deflection of the carrier drumsdrives the rolls towards the lowest point of deflection. Variations inthe web profile produce a "carrot shape" even in individual rolls, inwhich case the rolls tend to move in the lateral direction. Of course,variations in the lengths of the roll spools, together with the spoollocks, cause variation in the axial forces in different forms. It comesout from the above that there are a number of different reasons why therolls tend to be pressed against each other during winding.

In prior-art solutions, attempts have been made to attenuate thedetrimental oscillation occurring in carrier-drum winders by variousmeans. In the Patent DE-742,833 (granted Dec. 29, 1943), the problem ofoscillation of the rolls formed by winders of the carrier-drum type hasbeen described, and a solution has been described for reducing theoscillation. In this prior-art solution, the rolls are pressed lightlyby means of a cutting roll which operates as an extra support roll,whereby attenuation of the oscillation of the rolls is produced.

A similar attenuation of oscillation produced by means of a separateroll has been applied in the Patent DE-3,924,612.

With respect to the prior art, reference is also made to thepublications FI-841448 and FI-49,276, in which some typical carrier-drumwinders are described, in which, of course, the detrimental oscillationproblem of carrier-drum winders occurs.

It is a second prior-art mode of eliminating the problem of oscillationthat relative movements of the roll spools constituting the centers ofthe rolls are prevented either so that an axle is placed inside the rollspools, which axle keeps the central axes of the rolls immobile inrelation to one another, or so that the rolls are formed onto acontinuous roll spool. In both modes, it is a drawback that separationof the rolls formed from one another causes significant additional workand, thus, also reduced productivity. Moreover, when winding takes placearound the same center, the roll diameters become equally large, but,owing to variations in the cross-direction profile of the web, theirinternal tightness varies. This is not desirable in the procedures offurther processing of the rolls.

The problems described above occur in all such winder types in which thelocation/support of the web rolls that are formed comply with thefollowing terms:

the roll spools (web rolls) are placed one after the other coaxially sothat the location of each roll spool is determined by means of theadjacent roll spools.

the roll spools (web rolls) are supported under optimal conditions inthe radial direction of the rolls only (the spool locks just preventaxial movement arising from faults in the roll shapes and fromdeflection of the winding members).

OBJECTS AND SUMMARY OF THE INVENTION

The object of the present invention is to provide an improvement of themethod described above in winding. It is a specific object of theinvention to provide a method which solves the detrimental problem ofoscillation occurring. for example in carrier-drum winding better thanin the prior-art solutions.

The objectives of the invention are achieved by means of a method whichis characterized in that, in order to reduce the friction coefficient ofthe roll spools, before, or at the same time as, the roll spools areplaced in the winding position, the ends of the roll spools are treatedwith an agent that reduces the friction coefficient, or pieces of amaterial that has a low friction coefficient are placed at the ends ofthe roll spools, and/or the axial thrust force between the roll spoolsis lowered by passing a pressurized medium through the spool locks.

In the solution in accordance with the invention, it has been realizedto reduce the impulse that causes the oscillation. This is why, incarrier-drum winders, as a rule, it is no longer necessary to usevarious solutions of attenuation of oscillation, which require separatesolutions of additional equipment and, thus, result in additional costs.Thus, in the present invention, it has been noticed that the intensiveoscillation of the rolls during winding arises primarily from therelative movements of the roll spools and from the friction forcesbetween the roll spools. In the present invention, it has been realizedto reduce the friction forces between the roll spools.

In a preferred embodiment of the invention, the friction efficient islowered by lubricating the ends of the roll spools with oil, which isabsorbed into the end of the roll spool and which reduces the frictioncoefficient between the ends of the roll spools, in which connection thefriction force is also lowered, and so also the impulse that producesthe detrimental oscillation. Of course, according to the invention, thefriction coefficient can also be lowered by means of other substancesthat are applied to the ends of the roll spools and that lower thefriction coefficient, for example by means of waxes or fats.

In a second preferred embodiment of the invention, the contact force,i.e. the axial thrust force, between the ends of the roll spools, islowered by feeding a pressurized medium, preferably compressed air, intothe row formed by the roll spools, for example, through the spool locks,in which connection the compressed air discharged between the rollspools attempts to keep the rolls that are being formed apart from oneanother and thereby reduces the friction force between the roll spools.For example, if the set of spools is "excessively long", the supply ofcompressed air also reduces the axial thrust forces of the spool locksand, thus, the impulse that causes the detrimental oscillation.

The most significant advantage that is obtained by means of theinvention is therein that, when the impulse that causes the oscillationis reduced substantially in carrier-drum winders it is, as a rule,unnecessary to lower the winding speed, i.e. to reduce the capacity ofthe machine.

The invention will be described in detail with reference to somepreferred embodiments of the invention illustrated in the figures in theaccompanying drawings, the invention being, however, not supposed to beconfined to said embodiments alone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a conventional carrier-drumslitter-winder.

FIG. 2 is a schematic illustration viewed from ahead of a problemoccurring in a carrier-drum slitter-winder as shown in FIG. 1.

FIG. 3 is a schematic illustration viewed from ahead of a second problemoccurring in a carrier-drum slitter-winder as shown in FIG. 1.

FIG. 4 is a schematic illustration on an enlarged scale of the detail Ataken from FIG. 2 and showing the way in which the ends of two adjacentroll spools contact each other.

FIG. 5 is a top view of a preferred solution of equipment for treatmentof the ends of the roll spools with an agent that lowers the frictioncoefficient.

FIG. 6 is a sectional view taken along the line VI--VI in FIG. 5.

FIG. 7 shows a second preferred embodiment for treatment of the ends ofthe roll spools in a way that lowers the friction coefficient.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIGS. 1 . . . 4, the carrier-drum slitter-winder is denoted generallywith the reference numeral 10. The carrier-drum slitter-winder comprisesa first carrier drum 11 and a second carrier drum 12. The rolls that arebeing formed are denoted with the reference numerals 13a,13b,13c,13d,13eand 13f. The reference numeral 14 denotes the rider roll. The rollspools of the rolls are denoted with the reference numerals15a,15b,15c,15d,15e and 15f. The spool locks that prevent axialmovements of the lateral rolls are denoted with the reference numeral16.

The distance s between the web rolls is regulated by means of a webseparation device before the winding, so that the rolls do not adhere toone another as a result of relative overlapping of the separate webs.

FIGS. 2 and 3 show the differences in web roll diameters arising fromtwo different profiles of material web, which differences in diameterscause shifting of the roll spools 15a,15b,15c,15d,15e and 15f so thattheir axes of rotation are not on the same line, compared with oneanother.

In FIG. 4 it is shown how the ends of, for example, the roll spools 15aand 15b reach contact with one another. The distance between the rolls13a and 13b is denoted with the letter s.

In FIGS. 5 and 6, the device for treatment of the ends of the rollspools with an agent that lowers the fiction coefficient is denotedgenerally with the reference numeral 20. In this embodiment the device20 comprises an oil space 21, in which there is oil 22. The referencenumeral 23 denotes the roll, i.e. the oil transfer wheel, and thereference numeral 24 denotes the spool pusher. The reference numeral 26denotes the filling opening and the plug of the oil tank 21. Thereference numeral 27 denotes the plate between the spool pusher 24 andthe oil tank 21. During the pushing movement, the roll 23 that is in anoil bath transfers oil 22 to the end of the roll spool 15. The referencenumeral 25 denotes the wheel that rotates the spool, by means of whichwheel the revolving movement of the roll spool 15 is produced. Owing tothe solution, the end of the roll spool 15 is lubricated very well withoil, in which connection the friction coefficient between the ends ofthe roll spools 15 is lowered to a considerable extent.

In the embodiment shown in FIG. 7, the friction coefficient of the endof the roll spool 15 is lowered by to the end of the roll spool 15fitting an end piece 17 that has a low friction coefficient. In thisembodiment, a flange-shaped or sleeve-shaped end piece 17 has been used,which has been attached to the roll spool 15 by means of O-ring seals18.

Above, just some preferred embodiments of the invention have beendescribed, and it is obvious to a person skilled in the art thatnumerous modifications can be made to said embodiments within the scopeof the inventive idea defined in the following patent claims.

I claim:
 1. A method in winding, wherein a number of separate rolls areformed side by side around separate roll spools placed axially one afterthe other while supported by first and second carrier drumscharacterized in that, in order to reduce the friction coefficient ofthe roll spools during winding when the ends of the roll spools areliable to contact one another before, or at the same time as, the rollspools are placed in the winding position, the ends of the roll spoolsare treated with an agent that reduces the friction coefficient, orpieces of a material that has a low friction coefficient are placed atthe ends of the roll spools, and/or axial thrust force between the rollspools is lowered by passing a pressurized medium through the spoollocks.
 2. A method as claimed in claim 1, characterized in that oil isused as the agent that lowers the friction coefficient.
 3. A method asclaimed in claim 1, characterized in that a wax is used as the agentthat lowers the friction coefficient.
 4. A method as claimed in claim 1,characterized in that a fat is used as the agent that lowers thefriction coefficient.
 5. A method as claimed in claim 1, characterizedin that flange-shaped members (17) that are fitted to the ends of theroll spools (15a,15b,15c,15d,15e,15f) are used as the pieces of materialthat lower the friction coefficient.
 6. A method as claimed in claim 1,characterized in that compressed air is used as the pressurized medium.7. In a method for winding a material web in which a plurality ofseparate rolls are formed each around a respective roll spool, the rollsbeing arranged one after another and side by side such that at least twoof the roll spools are axially adjacent one another, the rolls beingsupported by first and second carrier drums, the improvement comprisingthe step of:reducing friction between ends of the adjacent roll spoolsduring winding of the web onto the adjacent roll spools when the ends ofthe roll spools are liable to contact one another.
 8. The method ofclaim 7, wherein said friction reducing step comprises the step oftreating the ends of at least one of the adjacent roll spools with anagent that reduces the friction coefficient of the material of the atleast one roll spool during winding of the web onto the adjacent rollspools.
 9. The method of claim 8, further comprising the step ofutilizing oil as the agent that reduces the friction coefficient of theat least one roll spool.
 10. The method of claim 8, further comprisingthe step of utilizing wax as the agent that reduces the frictioncoefficient of the at least one roll spool.
 11. The method of claim 8,further comprising the step of utilizing a fat as the agent that reducesthe friction coefficient of the at least one roll spool.
 12. The methodof claim 7, wherein said friction reducing step comprises the step ofprior to winding of the web onto the adjacent roll spools, arranging amaterial having a friction coefficient lower than the frictioncoefficient of the material of the roll spool at least at one of theends of at least one of the adjacent roll spools in contact with anopposed roll spool.
 13. The method of claim 12, further comprising thestep of inserting a flange-shaped member into the at least one end ofthe roll spool, said flange-shaped member providing the material havinga friction coefficient lower than the friction coefficient of thematerial of the roll spools.
 14. The method of claim 7, wherein saidfriction reducing step comprises the step of directing a pressurizedmedium from a spool lock preventing axial movement of the rolls throughthe roll spools to lower axial thrust between the adjacent roll spoolsduring winding of the web onto the roll spools, the pressurized mediumbeing discharged between the adjacent roll spools to thereby reduce thefriction force between the adjacent roll spools.
 15. The method of claim14, further comprising the step of utilizing compressed air as thepressurized medium.
 16. In an apparatus for winding a material web inwhich a plurality of separate rolls are formed each around a respectiveroll spool, the rolls being arranged one after another and side by sidesuch that the roll spools are axially adjacent one another, the rollsbeing supported by first and second carrier drums, the improvementcomprising;means for reducing the friction between ends of the adjacentroll spools during winding of the web onto the adjacent roll spools whenthe ends of the roll spools are liable to contact one another.
 17. Theapparatus of claim 16, wherein said means comprise a receptaclereceivable of a liquid substance and a transfer wheel for transferringthe liquid substance from said receptacle to the ends of the adjacentroll spools.
 18. The apparatus of claim 17, wherein the liquid substanceis oil.
 19. The apparatus of claim 16, wherein said means comprises aflange-shaped end piece inserted at least partially into the ends ofeach of the adjacent roll spools prior to the winding of the web ontothe adjacent roll spools, said end pieces being made of a materialhaving a friction coefficient lower than the friction coefficient of thematerial of the adjacent roll spools such that friction between the endsof the adjacent roll spools is reduced during winding of the web ontothe adjacent roll spools.
 20. The apparatus of claim 16, wherein saidmeans comprise spool locks engaging with axial ends of the adjacent rollspools, said spool locks being structured and arranged to direct apressurized medium through the adjacent roll spools to be dischargedbetween the adjacent roll spools to thereby reduce the friction forcebetween the adjacent roll spools.